U.S. patent application number 10/258166 was filed with the patent office on 2003-03-27 for gas cell.
Invention is credited to Martin, Hans Goran Evald.
Application Number | 20030058439 10/258166 |
Document ID | / |
Family ID | 20279425 |
Filed Date | 2003-03-27 |
United States Patent
Application |
20030058439 |
Kind Code |
A1 |
Martin, Hans Goran Evald |
March 27, 2003 |
Gas cell
Abstract
The invention relates to a gas cell (2') that includes a cavity
(20) for a chosen gas volume, a light source (30), and one or more
light bundle receiving units or detectors (21, 22, 23, 24, 25). The
cavity (20) is formed by and delimited by, inter alia, a first
partially elliptical mirror surface (20a) and two partially
elliptical mirror surfaces, a second (20b) and a third (20c), which
are opposed to said first mirror surface (20a) and which are so
orientated in relation to each other that a light bundle (130a,
130b) will be reflected by said mirror surfaces (20a, 20b, 20c) so
as to form an optical measurement path extremity, and terminate in
a light-receiving unit (21, 22, 23, 24, 25) allocated to a chosen
measurement path extremity. The light source (30) is disposed in
one end region of said cavity (20) and a reflector (30a, 30b) which
functions to cause emitted light bundles to converge towards a
focusing point (F) is also disposed in said one end region.
Inventors: |
Martin, Hans Goran Evald;
(Delsbo, SE) |
Correspondence
Address: |
OSTROLENK FABER GERB & SOFFEN
1180 AVENUE OF THE AMERICAS
NEW YORK
NY
100368403
|
Family ID: |
20279425 |
Appl. No.: |
10/258166 |
Filed: |
October 17, 2002 |
PCT Filed: |
April 26, 2001 |
PCT NO: |
PCT/SE01/00901 |
Current U.S.
Class: |
356/246 |
Current CPC
Class: |
G01N 21/03 20130101 |
Class at
Publication: |
356/246 |
International
Class: |
G01N 001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 26, 2000 |
SE |
0001509-9 |
Claims
1. A gas cell that includes a cavity (20) adapted for a chosen gas
volume, a light source (30), and units (21-25) for receiving one or
more bundles of light rays, wherein the cavity is formed and
delimited by, inter alia, a first partially elliptical mirror
surface (28), two partially elliptical mirror surfaces, a second
surface (20b) and the third surface (20c), disposed opposite to
said first surface (20a) and orientated in relation to each other
so that light bundles (130a, 130b) emitted from the light source
(30) will be reflected by said mirror surfaces (20a, 20b, 20c) such
as to form an optical measurement path extremity and terminate in a
unit (21-25) that receives an allocated a light bundle in a chosen
measurement path extremity, characterized in that said light source
(30) is disposed in one end-region of said cavity (20); and in that
there is disposed in said one end-region a reflector (30a, 30b)
that causes the emitted light bundles to converge towards a
focusing point (F).
2. A gas cell according to claim 1, characterized in that said
reflector is adapted to cause said light bundles to converge
towards a focusing point (F) located within the cavity.
3. A gas cell according to claim 2, characterized in that said
focusing point (F) is located adjacent a flat cavity-associated
mirror part (20d).
4. A gas cell according to claim 1 or 3, characterized in that a
virtual focusing point (F') formed by a mirror section is located
outside said cavity.
5. A gas cell according to claim 1 or 3, characterized in that the
flat mirror section (20d) is disposed adjacent a delimiting surface
of said first mirror surface (20a).
6. A gas cell according to claim 1, characterized in that said
reflector is comprised of a partially elliptical section orientated
adjacent said first mirror surface.
7. A gas cell according to claim 1, characterized in that said
reflector is comprised of a partially elliptical section formed by
a wall-part disposed within the cavity.
8. A gas cell according to claim 1, characterized in that the
cavity is thin and formed by at least two parts that can co-act
with one another.
9. A gas cell according to claim 1 or 3, characterized in that a
gas connection is disposed adjacent said flat mirror section.
10. A gas cell according to claim 1 or 7, characterized in that a
gas connection is disposed adjacent said light source and adjacent
a wall section disposed within the cavity.
11. A gas cell according to claim 1, characterized in that the
light bundles are reflected from said virtual focusing point to a
border region orientated between the second and the third mirror
surfaces; and in that a first part, reflected by the second mirror
surface, forms a first optical measurement path extremity, while a
second part, reflected by the third mirror surface, forms a second
optical measurement path extremity.
12. A gas cell according to claim 1 or 3, characterized by a device
located adjacent the light source and functioning to deflect a
light bundle, emitted from the light source, in a direction towards
the flat mirror section, therewith to form a further optical
measurement path extremity.
13. A gas cell according to claim 1, characterized in that it
includes cavity-associated active optical surfaces that are
concentrated on respective sides of the light source and towards
partially elliptical reflector-adapted sections and that converge
towards a focusing point, said surfaces being comprised of a
surface region located between the elliptical mirror surfaces.
14. A gas cell according to claim 12, characterized in that said
device is adapted to allow shadowing of direct-acting light bundles
to cavity-associated light detectors.
15. A gas cell according to claim 1, characterized in that said
light source is adapted for infrared radiation and intended for
determining moisture content (steam) via a selected detector.
16. A gas cell according to claim 1, characterized in that selected
units or detectors for receiving the light bundles are adapted to
determine the concentration of a chosen gas, such as carbon
dioxide, carbon monoxide, nitrous oxide.
17. A gas cell according to claim 1, characterized in that a
cavity-associated wall section is comprised of a diffusion
filter.
18. A gas cell according to claim 1, characterized in that the
thickness of the cavity is adapted to the length (height) of an
incandescent filament for the light source.
Description
FIELD OF INVENTION
[0001] The present invention relates generally to a gas cell and
more specifically to a gas cell of the kind that includes a cavity
for accommodating a chosen gas volume, a light source, and units
for receiving one or more light beams or bundles of light rays.
[0002] More particularly, the invention relates to a gas cell of
this kind in which the cavity is formed and defined by a first,
partially elliptical mirror surface that faces towards two
partially elliptical mirror surfaces, i.e. a second and a third
mirror surface.
[0003] These elliptical mirror surfaces are so orientated in
relation to each other that a light beam emitted from the light
source will be reflected by said mirror surfaces so as to provide
an optical measuring path extremity and terminate in a receiving
unit intended for a selected path extremity.
[0004] By the expression "partially elliptical" shall be understood
solely a part of a full elliptical shape on the one hand and an
elliptical shape that conforms essentially with a mathematical
elliptical shape on the other hand.
DESCRIPTION OF THE BACKGROUND ART
[0005] It has long been known to use electromagnetic waves in
connection with absorption spectroscopy, and then particularly
light beams or bundles of light rays (light bundles) whose
frequencies lie within the infrared range, and to use different
types of detector elements.
[0006] In the case of gas sensors that are based on absorption
technology, the light beams shall be permitted to pass through a
gas sample contained in a cell cavity, wherewith a given volume of
a selected gas will result in frequency-dependent absorption of the
light beams.
[0007] A gas detector is thus adapted to detect the frequency
spectrum of the light beams for a relevant gas or gas concentration
within the cavity, and the gas or gas concentration can be
determined by evaluating the intensity of the detected light beam
in relation to a chosen intensity for the incident light beams and
the absorption coefficient of the light concerned or the
electromagnetic wavelength in the gas concerned.
[0008] With regard to the features of the present invention, it can
be mentioned that it is known to compress a gas cell with respect
to its physical dimension, by allowing the light beams to be
reflected a number of times within the cavity, thereby to obtain a
relatively long optical measurement path extremity (wavy length) or
a relatively long absorption path extremity relative to the
internal dimensions of the gas cell or the cavity.
[0009] The absorption cell or gas cell disclosed in Patent
Publication U.S. Pat. No. 5,009,493 is an example of a gas cell
that is designed to provide an adapted long absorption path
extremity or an optical measuring path extremity within a defined
or delimited cavity, where incoming light beams (or light bundles)
shall be reflected a number of times within the cavity before being
exited therefrom and thereafter fall on a light detector.
[0010] In gas cells of this kind, it is usual to allow incoming
light beams to pass into the cavity via a first opening, and to
exit the beams from the cavity via a second opening, therewith
enabling a detector that is used in the present context to consist
of a separate unit that is preferably mounted on the gas cell in
connection with the second opening.
[0011] The cavity of the gas cell is formed normally by at least a
first and a second part, whose inner surfaces may be treated to
provide surfaces that strongly reflect the incoming light beams or
light bundles.
[0012] This surface treatment normally comprises coating the inner
surface with one or more layers of metal, wherewith the reflecting
surfaces are formed by the last metal layer applied.
[0013] The metal and procedure chosen for this coating process will
depend on the desired optical qualities of the surfaces and also on
the optical wavelength or wavelengths that shall be reflected by
said surfaces. The material in the gas cell body shall also be
taken into consideration.
[0014] With regard to the significant characteristic features and
properties of the present invention, mention shall also be made to
an example of an earlier known gas sensor in which incoming light
beams or light bundles are reflected a number of times within the
cavity in accordance with a predetermined pattern.
[0015] In this respect, reference is made to a gas sensor that is
illustrated and described in International Patent Application
PCT/SE96/01448, Publication No. WO97/10460 and the International
Patent Application PCT/SE97/01366, Publication No. WO98/09152, from
which the present invention can be considered to constitute a
development.
SUMMARY OF THE INVENTION
[0016] Technical Problems
[0017] When taking into consideration the technical deliberations
that a person skilled in this particular art must take in order to
provide a solution to one or more technical problems that he/she
encounters, it will be seen that it is necesssary initially to
realise the measures and/or the sequence of measures that must be
taken to this end on the one hand, and on the other hand to realise
which means is/are required to solve one or more of said problems.
On this basis, it will be evident that the technical problems
listed below are highly relevant to the development of the present
invention.
[0018] When considering the present state of the art as described
above, it will be seen that in respect of a gas cell of the kind
described in the introduction a technical problem resides in
creating conditions which enable a chosen adapted optical measuring
path extremity to be longer than the measuring path extremities
that can be obtained with the aforesaid international patent
publications below a limited increase in size of the cavity
used.
[0019] Another technical problem resides in realising the
significance of and the advantages gained by allowing said light
source to be disposed within one end-region of said cavity, so as
to be able to create conditions that provide advantages over those
that can be afforded by earlier known technology.
[0020] A further technical problem resides in realising the
significance of and the advantages afforded by disposing in said
one end-region a reflector that causes the emitted light bundles to
converge.
[0021] It will also be seen that a technical problem resides in
realising the significance of and the advantages afforded by
adapting said reflector so as to cause the light bundles to
converge towards a focusing point which becomes located within the
cavity.
[0022] Another technical problem is one of realising the
significance of and the advantages gained by allowing said focusing
point to be situated adjacent a flat mirror part associated with
said cavity.
[0023] Another technical problem is one of realising the
significance of and the advantages afforded by allowing a virtual
focusing point created via said flat mirror part to be located
outside said cavity.
[0024] A further technical problem is one of realising the
significance of and the advantages afforded by disposing the flat
mirror part adjacent a first delimiting surface of said first,
partially elliptical, mirror surface.
[0025] Another technical problem is one of realising the
significance of and the advantages associated with allowing said
reflector to be comprised of a partially elliptical section
adjacent a second delimiting surface of said first, partially
elliptical, mirror surface.
[0026] It will also be seen that a technical problem resides in
realising the significance of allowing the reflector to be
comprised of a partially elliptical section formed by a wall
portion placed in the cavity.
[0027] Another technical problem is one of realising the
significance of and the advantages gained by the ability to create
in a gas cell of the kind concerned conditions which will enable a
thin cavity to be chosen and said cavity to be formed by at least
two mutually co-acting parts.
[0028] A technical problem also resides in realising the
significance of and the advantages associated with allowing a gas
connection to the cavity to be disposed adjacent the aforesaid flat
mirror part.
[0029] Yet another technical problem is one of realising the
significance of and the advantages gained by allowing a gas
connection to the cavity to be disposed adjacent a light source and
adjacent the wall-part placed in the cavity.
[0030] Another technical problem resides in the ability to realise
the significance of and the advantages gained by enabling the light
bundle to be reflected from said virtual focusing point to a border
region between the second and the third partially elliptical mirror
surface and to allow a first part of the light bundle, reflected by
the second mirror surface, to be allocated to a first optical
measuring path extremity, and to assign another part of the light
bundle, reflected by the third mirror surface, to a second optical
measuring path extremity.
[0031] In the case of a gas cell of the kind described in the
introduction, a technical problem resides in the ability to realise
the significance of and the advantages gained by means for
deflecting a direct-acting light bundle from the light source
disposed adjacent said light source and directed towards the flat
mirror part, such as to be able to form a further optical, although
short, measuring path extremity.
[0032] Another technical problem resides in the ability to realise
the significance of and the advantages associated with allowing
cavity-associated active optical surfaces to be concentrated on a
respective side of the light source and towards partially
elliptical reflector-adapted sections and optical surfaces that
converge towards a focusing point and a surface region orientated
between the three partially elliptical mirror surfaces.
[0033] Another technical problem resides in the ability to realise
the significance of and the advantages associated with allowing
said means to be adapted for shadowing direct-active light bundles
from the light source to the cavity-associated light detectors.
[0034] A further technical problem resides in the ability to create
with the aid of simple means and with a gas sensor of limited form
conditions such that the gas sensor can be readily caused to
measure moisture content, or water vapour concentration, or,
alternatively, the presence of and the concentration of some other
chosen gas, such as carbon dioxide, carbon monoxide, nitrous oxide,
etc.
[0035] Solution
[0036] The present invention is thus based on a gas cell of the
kind described in the introduction that includes a cavity adapted
for a chosen gas volume, a light source, and one or more units for
receiving light beams and light bundles, wherein said cavity is
formed and delimited by a first partially elliptical mirror surface
facing towards two partially elliptical mirror surfaces, a second
and a third surface, said surfaces being mutually orientated so
that a light bundle emitted from the light source will be reflected
by said mirror surfaces, preferably a number of times, so as to
form an optical measuring path extremity, and terminate in a light
bundle receiving unit associated with a chosen optical measuring
path extremity.
[0037] With the intention of solving one or more of the aforesaid
technical problems, it is proposed in accordance with the invention
that the light source is disposed within the cavity and then within
its one end-region, and that there is disposed in said end-region a
reflector which causes the emitted light bundles to converge
towards a focusing point.
[0038] By way of proposed embodiments that lie within the scope of
the inventive concept, it is proposed that the reflector is adapted
to allow the light bundles to converge towards a focusing point
located within the cavity and within its other, opposite
end-region.
[0039] It is also proposed that said focusing point shall be
located adjacent to but at a given path extremity from a flat
cavity-associated mirror part.
[0040] In this regard, it is proposed that a virtual focusing point
formed by the flat mirror part is located outside said cavity.
[0041] According to the invention, the flat mirror part shall be
disposed adjacent a first delimiting surface of said first,
partially elliptical mirror surface.
[0042] The reflector mentioned is comprised of a partially
elliptical section adjacent said first, partially elliptical mirror
surface.
[0043] The reflector is also comprised of a partially elliptical
section formed by a wall-part disposed in the cavity.
[0044] It is particularly proposed that the cavity is very thin and
that it can be formed or produced from at least two mutually
co-acting parts.
[0045] It is also proposed in accordance with the invention that a
first gas connection shall be disposed adjacent said flat mirror
part, and that a second gas connection shall be disposed adjacent
to the gas source and adjacent the wall-part fastened in the
cavity.
[0046] It is also proposed in accordance with the present invention
that the cavity of the gas cell shall be formed so that the light
bundles will be reflected from said virtual, cavity-peripheral
focusing point to a border region between the second and the third
mirror surface, and that a first part, reflected by the second
mirror surface, forms a first optical measuring path extremity,
while a second part, reflected by the third mirror surface, forms a
second optical measuring path extremity.
[0047] According to the invention, a device for deflecting a
direct-acting light bundle from the light source is provided
adjacent the light source and within the cavity, said device facing
towards the flat mirror part, such as to therewith form a further
optical measuring path extremity.
[0048] It is also proposed in accordance with the invention that
cavity-associated active optical surfaces shall be concentrated on
their respective sides of the light source and extend towards
partially elliptical, reflector-associated sections and, moreover,
converge towards the cavity-internal focusing point and a surface
region disposed between the three partially elliptical mirror
surfaces.
[0049] It is also proposed that said device shall be designed and
adapted to shadow direct-acting light bundles to cavity-associated
light detectors.
[0050] According to the invention, the light source may be adapted
for infrared radiation and is intended to enable moisture contents
to be measured.
[0051] The units that receive the light beam or light bundle are
adapted to determine the presence of and/or the concentration of
other selected gases, such as carbon dioxide, carbon monoxide,
nitrous oxide, etc.
[0052] Advantages
[0053] Those advantages primarily characteristic of an inventive
gas cell having characteristic significance of the present
invention reside in the provision of conditions capable of
providing in a gas cell of small external dimensions at least two
long optical measurement path extremities. In addition, measures
have been taken for causing a gas volume to pass through the cavity
in lamina flow or essentially lamina flow.
[0054] The gas cell can also be used to provide a further, albeit
short, measurement path extremity.
[0055] The primary characteristics of an inventive gas cell are set
forth in the characterising clause of the accompanying claim 1.
BRIEF DESCRIPTION OF THE DRAWINGS
[0056] An embodiment at present preferred and having characteristic
features significant of the invention will now be described in more
detail by way of example and with reference to the accompanying
drawings, in which
[0057] FIG. 1 is a block diagram illustrating a gas detector that
uses an inventive gas cell;
[0058] FIG. 2 is a plan view showing the form of an inventive gas
cell;
[0059] FIG. 3 is a sectioned view taken on the line III-III in FIG.
2;
[0060] FIG. 4 illustrates a gas cell according to FIG. 1 and shows
optically active illuminating surfaces; and
[0061] FIG. 5 illustrates the gas cell according to FIG. 2 showing
active illumination surfaces and a periscope shadow formed by a
device, and the surface area within which direct radiation from the
light source onto light detectors or units shall be prevented.
DESCRIPTION OF EMBODIMENTS AT PRESENT PREFERRED
[0062] Referring to FIG. 1, there is shown schematically a detector
arrangement for enabling the presence of a gas and/or a gas
concentration in/of a gas mixture to be determined.
[0063] The arrangement shown in FIG. 1 is referenced 1 and includes
a requisite gas sensor 2 which is connected to a connection 2a and
to a connection 2b which enable a volume of gas to be assayed to be
delivered to and exited from the gas cell.
[0064] By way of an alternative, a wall-part 20' may serve as a
diffusion filter.
[0065] It is assumed that the gas is introduced via the connection
2a and allowed to pass through a gas cell 2' in the gas sensor 2 in
a more or less lamina flow, and thereafter to exit through the
connection 2b.
[0066] FIG. 1 also shows the connection of one or more units 21,
22, 23, 24 and 25 to a central processing unit 3, said units being
intended to receive light beams or light bundles.
[0067] The central unit 3 thus includes necessary signal processing
circuits and circuits for emitting and activating a gas sensor
associated light source via a line 3a.
[0068] The present invention relates primarily to a gas sensor 2'
in the gas cell 2, this gas sensor being described in more detail
below with reference to FIGS. 2 and 3.
[0069] The gas cell 2' includes the cavity 20, which is adapted for
a chosen gas volume, a light source 30, and one or more light beam
receiving units 21-25.
[0070] The cavity 20 is formed and delimited by, inter alia, a
first partially elliptical mirror surface 20a and two partially
elliptical mirror surfaces, a second 20b and a third 20c, which lie
opposite the first mirror surface 20a.
[0071] The three mirror surfaces 20a, 20b, 20c are so orientated in
relation to each other that the light beam emitted from the light
source 30 will be reflected between said mirror surfaces and
therewith be able to form an optical measuring path extremity or
path extremities, and terminate in a light beam receiving unit or
detector to which a chosen measuring path extremity is
allocated.
[0072] The light source 30 is disposed in one end-region of the
cavity, the left region in FIG. 2, and a reflector that causes a
chosen light beam to converge is disposed in said one end-region
and comprises an upper part 30a, and a lower part 30b, with the
light source 30 placed in a focusing point.
[0073] The reflector parts 30a, 30b are partially elliptical and
adapted to cause the chosen light ray bundles or groups to converge
towards a focusing point F in the cavity 20, such as respective
light bundles 130 and 230.
[0074] The focusing point F is located in the region of the other
end of the cavity, to the right in FIG. 2.
[0075] The focusing point F is located adjacent a flat
cavity-associated mirror part 20d. This flat mirror part 20d is
angled somewhat in relation to a straight line between the light
source 30 and the focusing point F.
[0076] The flat mirror part 20d creates from the focusing point F a
virtual focusing point F', which will now be spaced slightly
outside the cavity 20, as clearly shown in FIG. 2.
[0077] The flat mirror part 20d is disposed adjacent a right-hand
delimiting surface of the first mirror surface 20a.
[0078] The upper mirror surface 30a of the reflector is comprised
of a partially elliptical section and is located adjacent a
left-orientated delimiting surface of the first mirror surface
20a.
[0079] The reflector-associated part 30b is also comprised of a
partially elliptical section formed by a partially elliptical
wall-part 26 disposed in the cavity 20.
[0080] Referring to FIG. 3, it will be seen that the cavity 20 may
be very thin or narrow and that it is defined primarily by two
mutually co-acting parts 41, 42. The thickness may conform to the
length of an incandescent filament for the light source 30, i.e. a
length of 1.5 mm or slightly there above.
[0081] A first gas connection 2a is disposed adjacent said flat
mirror part 20d.
[0082] A second gas connection 2b is disposed adjacent the light
source 30 and adjacent the wall-part 26 positioned in the cavity
20.
[0083] In addition to forming the mirror part 30b, the wall-part 26
is adapted, as a result of its thickness and shape, to be able to
provide a pronounced lamina flow of the gas volume to be assayed,
said gas volume being assumed to be introduced through the
connection 2a and exited through the connection 2b.
[0084] In accordance with the invention, the bundles of light rays,
such as the light bundles 130 and 230, are reflected from said
virtual focusing part F' to a boundary region located between the
second mirror surface 20b and the third mirror surface 20c, and
that a first part 130a, reflected by the second mirror surface 20b,
forms a first optical measurement path extremity, whereas a second
part 130b, reflected by the third mirror surface 20c, forms a
second optical measurement path extremity.
[0085] As will be understood, each of these optical measurement
path extremities may be divided into further measurement path
extremities as the light is reflected between the surfaces 20a, 20b
and 20c, in a manner known per se. Each optical measurement path
extremity terminates in a chosen detector 21, 22, 23, 24 and 25
respectively.
[0086] Located adjacent the light source 30 and facing towards the
flat mirror part 20d is a device 40 which is angled in respect to
direct-acting light bundles so as to be able to form a further (or
several) optical measuring path extremity (or path extremities) to
a light bundle receiving unit 43.
[0087] Shown in FIG. 4 are cavity-associated active optical
surfaces which are each concentrated on a respective side of the
light source 30, these surfaces being referenced 61 and 62.
[0088] These optical surfaces extend on respective sides of the
light source 30 towards the partially elliptical sections 30a, 30b
and cover those surfaces that converge towards the focusing point
F.
[0089] A further optical surface region 63 is defined between the
partially elliptical mirror surfaces 20a, 20b and 20c.
[0090] It will be seen particularly from FIG. 5 that said device 40
is adapted to enable shadowing of the direct-acting light bundles
to the cavity-associated light detectors 21-25.
[0091] The light source 30 may be adapted for infrared radiation
and intended, in this regard, for measuring the moisture content of
the cavity-enclosed gas volume, i.e. measurement of the water
vapour concentration.
[0092] The selected bundles of light rays may also be adapted to
enable the presence of and/or the concentrations of another chosen
gas to be determined, such as carbon dioxide, carbon monoxide,
nitrous oxide, through the medium of said light-receiving circuits
or units.
[0093] Referring back to FIGS. 2 and 3, it will be noted that the
additional optical measurement path extremity, between the light
source 30 and the unit 41 can be given a short length, such as a
length of 4-20 mm or about 8 mm.
[0094] The optical measurement path extremity to the unit 21 or 23
may be given a length of 13 or 21 cm respectively, and the optical
measurement path extremity between the light source 30 and
respective units 23, 24, 25 may be given a length of 21, 29 or 37
cm respectively.
[0095] It will also be noted that in the case of a gas cell 2'
having external measurements of about 45.times.45 l mm, it is
therewith possible to provide at least two mutually independent
optical measurement path extremities that have a length of 36 cm,
so as to be able to determine the concentration of nitrous
gas/carbon dioxide and the water content of the gas and its carbon
dioxide concentration.
[0096] It will be understood that the invention is not restricted
to the aforedescribed exemplifying embodiment thereof and that
modifications can be made within the scope of the inventive concept
as illustrated in the accompanying claims.
* * * * *